Here is attached a link to my Pelican 928 section where is more about this 928 and three other of my 928 developments. That section has stayed relatively quiet, but this summer I really got further with our forever projects.
That particular car is simply original Strosek GTR bodywork (front bumper and side skirts) as was in Max & Moritz made 928 Cup car in 90ies.
http://forums.pelicanparts.com/porsche-928-technical-forum/468682-928-bolt-gluensmoothen-wide-body-kit-front-splitter-side-skirts-2.html
And as you can see my 911s has Strosek parts as well and my own bodywork alterations have been only make them more appropriate for racing purposes. Obviously I admire Vittorios design work throughout for 90ies cars. A sort of period correct parts I would say.